Just below Ross Lake, Diablo Lake is held back by the similarly huge 389ft Diablo Dam . A pullout off Hwy 20 known as the Diablo Dam Overlook provides incredible views of the turquoise-green lake framed by glacier-capped peaks. Diablo was the world's highest arch-type dam at the time of its completion in 1930, and building it in such a hostile region with no road access was one of the greatest engineering feats of the inter-war age.
Diablo Lake is popular with kayakers and canoeists (there's a launch site at Colonial Creek campground). The water's turquoise hue is a result of powdered rock ground down by glaciers.
North Cascades Environmental Learning Center , on the lake's northern banks, is operated by the North Cascades Institute in partnership with the National Park Service. The center offers a bevy of activities, many of them educationally oriented such as Lake Diablo Lake tours ($35) and Powerhouse tours ($40), as well as a variety of weekend retreats from $245, including on-site food and accommodation. If you just want lodging, you can rent rooms from $125 per night. Note that many of the excursions and lodging sell out even before summer starts. See the website for more details.
